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A291800
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Take n-th word over {1,2} listed in A291797 and apply the Post tag system described in A284116 (but adapted to the alphabet {1,2}); a(n) = length of first word we see in the orbit of that word that is in the cycle, if the orbit cycles, or 0 if the orbit reaches the empty string, or -1 if the orbit is unbounded.
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2
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0, 5, 0, 6, 15, 15, 0, 0, 0, 15, 15, 15, 15, 15, 0, 15, 0, 15, 15, 12, 15, 15, 15, 15, 19, 19, 13, 15, 0, 19, 0, 15, 15, 13, 0, 0, 15, 15, 15, 0, 0, 0, 13, 0, 19, 19, 13, 14, 0, 19, 19, 0, 17, 0, 13, 19, 0, 17, 19, 19, 31, 0, 0, 0, 15, 13, 13, 19, 13, 19, 0
(list;
graph;
refs;
listen;
history;
text;
internal format)
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OFFSET
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1,2
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COMMENTS
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Post's tag system maps a word w over {1,2} to w', where if w begins with 1, w' is obtained by appending 11 to w and deleting the first three letters, or if w begins with 2, w' is obtained by appending 2212 to w and deleting the first three letters.
We work over {1,2} rather than the official alphabet {0,1} because of the prohibition in the OEIS of terms (other than 0 itself) which begin with 0.
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LINKS
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CROSSREFS
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KEYWORD
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nonn
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AUTHOR
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EXTENSIONS
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STATUS
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approved
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